In order to prevent the rotation of a nut after tightening on a male part, an anti-rotation device must be integrated. Certain nuts of small size of the prior art have self-locking, but self-lockings are not adapted to nuts of large size. In fact, self-lockings are only available on nuts of 4 to 15.875 millimeters diameter.
Certain solutions of the prior art thus propose an anti-rotation function by collaboration between a finger and notches. For example, on the CFM56 aircraft engine, the anti-rotation function of a nut tightened on a turbine blade is assured via a ventilation tube situated inside the turbine blade. A finger is in fact installed on the ventilation tube, and accommodated in notches of the nut and the blade, then preventing the nut rotating around the blade. The ventilation tube being centred in several places, a tilting of the finger is impossible.
However, certain aircraft engines, for example the SilverCrest, do not have ventilation tubes inside the turbine blades, and more generally the male parts do not necessarily have a part installed inside the male part, on which to install a finger.